space

the set of all points

collinear points

points all in one line

coplanar points

points all in one plane

segment

two points on the line and all points between them

ray

a line with a single endpoint (or point of origin) that extends infinitely in one direction.

opposite rays

two rays that have the same endpoint and extend in opposite directions.

congruent segments

segments that have equal lengths

Midpoint

the point that divides the segment into two congruent segments.

segment bisector

is a point, a line, a ray or a line segment that bisects another line segment.

angle

a figure formed by two rays that have the same endpoint.

angle bisector

a ray that divides the angle into two congruent adjacent angles

supp. angles

Two angles whose measures have the sum 180

comp. angles

Two angles whose measures have the sum 90

vertical angles

Two angles whose sides form two pairs of opposite rays.

perpendicular lines

Two lines that interest to form right angles

acute angle

Angle with measure between 0 and 90

obtuse angle

Angle with measure between 90 and 180

right angle

Angle with measure of 90

straight angle

Angle with measure of 180

parallel lines

Coplanar lines that do not intersect

skew lines

Lines that aren't coplanar

scalene triangle

Triangle with no sides congruent

iso. triangle

Triangle with at least 2 congruent sides

equilateral triangle

Triangle with all sides congruent

acute triangle

Triangle with 3 acute angles

right triangle.

Triangle with one right angle

obtuse triangle

Triangle with one obtuse angle

equiangular triangle

Triangle with all angles congruent

exterior angle of a polygon

the angle formed when one side of a polygon is extended

diagonal

A segment joining non-consecutive vertices of a polygon

quadrilateral

a four-sided figure

triangle

a figure formed by three segment joining three noncollinear points.

pentagon

a 5-sided polygon

hexagon

a 6-sided polygon

median of a triangle

A segment from a vertex to the midpoint of the opposite side.

altitude of a triangle

The perpendicular segment from a vertex to the line containing the opposite side.

perpendicular bisector

A line, ray, segment that is perpendicular to the segment at it's midpoint

parallelogram

A quad. with both pairs of opposite sides congruent

rectangle

a quad. with four right angles

rhombus

a quad. with four congruent sides

square

a quad. with four right angles and four congruent sides.

trapezoid

A quad. with exactly one pair of parallel sides.

iso. trapezoid

A trapezoid with congruent legs

median of a trapezoid

the segment that joins the midpoints of the legs

bases of a trapezoid

Sides that are parallel in a Trapezoid

biconditional

A statement that contains "If and only If".

converse

Flips the if and then. Example: "If q, then p" would be "If p, then q".

inverse

Makes the statement negative. Example: "If q, then p" would be "If not q, then not p"

contrapostitive

Flips the if and then and makes the statement negative

similar polygons

Two polygons are similar if their vertices can be paired so that corresponding angles are congruent and corresponding sides are in proportion

ratio

The relationship between two quantities

proportion

equation stating that two ratios are equal

scale factor

The ratio of any two corresponding lengths in two similar geometric figures.